Recording apparatus



June 4, 1946. HELLMANN 2,401,350

RECORDING APPARATUS Filed April 17, 1944 6 Sheets-Sheet l mlljllllllfllllllllllllllllll IIIIIIIIHIIlllllllll:llllll]mnl Q J8 J9 a g b INVENTOR. Reinhard K lid/man.

June/4, 1946. R. K. HELLMANN 2,401,350

RECORDING APPARATUS Filed April 17, 1944 s Sheets-Sheet 2 IN VEN TOR.

Reinhard A. Hd/maim.

June 4, 1946. R. K. HELLMANN 2,401,350

RECORDING APPARATUS Filed April 17, 1944 6 Sheets-Sheet 3 mmvroze. Fem/7am lid/mam.

June 4, 1946. H R. K. HELLMANN 2,401,350

RECORDING APPARATUS Filed April 17, 1944 6 Sheets-Sheet 5 INVENTOR. Reinhard/d fleflma/m.

M WW- June 4, 1946. R. K. HELLMANN 2,401,350

RECORDING APPARATUS e sheets sheet s Filed April 17, 1944 a partially recorded diagram.

Patented June 4, 1946 UNITED STATES PATENT OFFICE,

2,401,350 Raconnnvo APPARATUS Reinhard K. Hellmann, Meriden, Conn, assignor to Connecticut Telephone 8 Electric Divlslon,. Great American Industries, Incorporated, Meriden, Conn, a corporation of Delaware Application April 17,

\ 18 Claims. 1

My inventionrelates to recording apparatus for measuring, signal-transmitting, facsimile transmitting or the like purposes andis related to the invention disclosed and claimed in the copending patent application of George Keinath and Reinhard K. I-lellmann for Recorders, Serial No. 531,375, filed April 1'7, 19%.

The known drum type recorders have a stylus which produces a record along the peripheral surface of a cylinder or drum member, usually by writing point or line marks on a recording sheet fastened around the cylindric member. The cylindric member and recording surface in known devices of this kind revolves about its axis I while the stylus moves in parallel thereto. The drum rotation and stylus travel are representa tive of the two coordinates, respectively, of the recorded diagram and are controlled in accord ance with two measuring quantities, one of which is i'requently time.

Compared with the so-called strip chart corders, i. e., recording apparatus in which a dia gram is plotted along a progressively vancing, non-rotating strip, the above-mentioned drum type recorders have the advantage permitting higher recording speeds and are often also tinguished by a relatively simple construction. As heretofore customary, however, these ers have the disadvantage that can not readily be observed while it i; recorded. This is particularly true aratus high operating speed as well tor multiple The application of strohoscopic observation means adds an intricacy and is not always satis factory. Hence, it is usually necessary to arrest the recorder drum in order to permit observing As a result, the recording operation must be interrupted during any such observation.

"It is an object of my invention to devise a recording apparatus that combines the advan-' tages of the above-mentioned known type re corders, i. e., permits a higher operating speed than the known strip chart recorders while avoiding the difficulty of observing the growing record heretofore peculiar to drum type recorders.

It is also an object of my invention to provide in. drum-type recording apparatus which, afiords visibility of the record any time during a recording operation without requiring an interruption of the operation.

Another object of my invention, allied to the one just mentioned is to devise a drum-type recorder in which the record or partial record remains stationary and hence is readily visible and 1944, Serial No. 531,374

observable during the entire recording procedure.

A further object is to provide a drum-type recorder in accordance with the aforementioned ob jects which is especially suitable for X-i record- 5 ing, 1. e, which can readily be applied in cases where neither component control quantity or diagram coordinate is necessarily proportional to 'time. i

A still further object of my invention is the provision of a'recording apparatus for producing a stationary record, especially at high speed operation, that is suitable for inkless recording as obtained, for instance, with electrolytic recording sheets known under the trade name Teledeltos paper. However, it is also an aim of my invention to aiiord the above-mentioned advantages with recorders of the continuously writing type such as ink and pen recorders.

lit is also an object of the invention to devise 1 a recording apparatus in which a. device for controlling the recording operation is combined with the recorder structure and operated by drive or transmission means for producing one or both components of the relative drum and stylus travel, so that the mechanically driven parts necessary for operating the apparatus form a single structural unit.

l-laving these objects in. mind, ll provide, ac-

cording to one feature of my invention, a record-.

Another feature of the invention consists in provictims a cylindric sheet-accommodating recorder member or drum that is stationary or non-rotating while the stylus means, rotating about the drum, produces the record but can be revolved 1 by the observer in order to place the record into a convenient position.

59 In another aspect of the invention, I provide an annular stylus carrier which surrounds a 037- lindrical recorder member and is capable of rotation about the axis of the recording sheet accommodated on the peripheral surface of the member,

65 cooperative drive means being provided to eflect a relative axial motion between sheet and stylus means during the rotation of the latter.

In a further aspect 01 the invention, the rotating stylus means of a recorder designed in ac cordance with one or several of the features aforementioned, or the drive for rotating the stylus means about the axis of the cylindric re cording surface, is connected by gears, shafts or the like transmissions with the movable control member cl a mechanism serving to control. the recording operation so that the control device Iorms part of the recording apparatus and oper ates in syncl'ironisrn with and in a given speed ratio to the rotations of the etylu The ahove-mentionod o objects and features of .tu oi .1 y it m dial ther cmllodiri log to the int i n;

Fig. ii is an explanatory diagram, ill an ink recorder on the principles of my ver by showing sci matically some of its mechanical parts in connection with the appertaining electric control means in a manner comparable that oi" Fig. 4; and

Figs. 10, 11 and 12, respectively, represent diagrammatically three further embodiments oi. mil invention each involving a recorder mechanism similar or related to that shown in Figs. 1 through 5.

Referring at first to the recording apparatus according to Figs. 1, 2 and 3, letter B denotes a base structure which comprises a housing I l with a closure plate l2 and forms a horizontal base plate 13. An insulator H screwed to plate l3 carries a. dowel pin I5 which engages the bottom plate I6 of the recorder drum D. The top plate ll of drum D, which like plate I8 is rigidly secured to the metallic drum cylinder 58, carries a stud IS with a knob of insulating material tlnnly mounted thereon. The stud I! is joinnalled in an insulating bearing plate 2|. An all-- nular end plate- 21, rigidly secured to the base structure B, has several dowels, like the one donoted by 23 in Fig. 1, which engage the bearing plate 2| for maintaining it in centered position. The drum D and its bearing plate 2| can be re moved, for the purpose of lastening recording paper to the drum cylinder l8, by pulling the entire drum assembly upwardly through the con-- ter opening 2! of the end plate 12.

The stylus assembly S of the recorder corn "ll view oi o recorder occo ill) prises an electrode pin 25 attached to an angular holder 26 which is pivoted at 21 to a. bracket II. This bracket is firmly mounted on a flange portion 29 of an annular carrier member M whose lower portion carries a gear 30. The flange portion 29 is engaged. by three equally spaced rollers 3t, 32 and 33 see Fig. 2i, revolvably mounted on an annular support 3 The two annular parts M and W urrou d t. drum D coaxlally but, while the c stylus assembly is rotatable alt support M is prevented from rotor lotion engagement or iced. screws to and 35 (Figs. 1, 2 and 3) se dig to advance the support El i along the drum, thereby moving her and stylus assembly in parallel oh i o. The

i u t e support c supper Jot or projection to i; the throne ring l2 one the feed ole ascend" ly carried by support 34 up and down along ti 1 r m.

t l 25 is normally held against the hill. ace oi. drum iii by means of a sprin M. It is desirable to hit the stylus pin when manually displacing the assembly. To this end, a pin 48 extends loosely through. the bracket 21B and carrier M so that its lower end lies closely above the skirt surface of cover member Ill. Member ID and sup port 34 are in threaded or cam engagement with each other at ll so that when the cover member 40 is rotated in order to release the carrier from the feed screws 35 and 3B, the cover member is also raised and lifts pin 45. As a result, holder 25 rotates counter-clockwise and lifts stylus 28 from the drum.

A modified structur for lifting the stylus is shown in Fig. 5. In this alternative construction, the stylus 25 is mounted on a lever 41 whose lower end, carries a weight 48. When the annular carrier M is non-rotating, the pendulum formed by the stylus, lever and weight is so balanced that the stylus point is lifted from the drum. During rotation of the carrier M, the weight 48 swings cular opening, so that the gear cannot rotate but is free to slide relatively to shaft 49. Gear has two hearings in i lay support 31 and in a strip ill soccer y, the strip being attached to support with clearance to accommodate the gear. Gear I meshes. with the sear portion it of carrier member M. v

It will be understood from the foregoing that, when shaft 48 is caused to revolve, carrier member M and stylus assembly 8 rotate about the drum D and at the same time can be displaced axially along the drum by revolving the feed screws 35 and 86.

The transmission and drive means for actuating the shaft and screws are mounted on or arranged within the housing H of base structure B as is apparent from Figs 1 and 3. These means, as exemplified in the embodiment here described, refer to a recorder for diagrams in which the coordinate parallel to the drum axis represents time or is proportional to time. Shaft 49 for rotating the stylus assembly carries at its end a bevel gear 52 meshing with a bevel gear 53 on the shaft 54 of an electric motor 55 which is mounted on base structure B. When the motor runs at constant speed, the stylus assembly is rotated about drum D ata speed determined by the trans mission ratio of gears 53 to 52, and 50 to 36. With a motor of 1800 R. P. M. rated speed, for in= stance, a stylus rotation of, say, 600 R. P. M. can be obtained for high-speed recording operation.

A pinion 56, also mounted on shaft 49, drives an idler gear 51, which in turn engages with gears SI and 59 fastened to the feed screws 35 and 86 respectively. Consequently the two feed shafts will revolve at a fixed speed relative to that of the stylus rotation and move the stylus slowly along the drum, for instance, from the top to the bottom of the drum, the resultant stylus motion being alonga helical path of many turns so asto scan the entire area of the recording surface during each complete recording period. At the end of its downward travel, the carrier may actuate a limit switch (not shown) which stops the-drive or disengages the carrier from the feed screws.

During the just-mentioned scanning motion, the stylus 22* runs idle, that is, it produces he recording merits on the sheet placed on the drum D except at one or several points of each individual stylus rotation at which an electric current is passed between stylus and drum through the electro-responsive recording paper mounted on the drum. The electric means for controlling this marking operation comprise a variable circuit member, preferably an impedance or potenti ometric device,- which has a movable adjusting or control member actuated in a fixed speed relation to one component of the stylus motion relative to the drum. In the embodiment of Figs. 1 to 3, theielectric device for controlling the stylus operation consists of a resistance potentiometer P (Figl) which has an insulating base 68 mounted on three studs El, 62 and 63 (Figs, 1 and 3) fastened to the base plate II. The base 80 carries and encloses a resistor 88 (in Fig. 4) and has a bottom plate 64 (Fig. 1) provided with a number of contacts, such as those denoted by 85, which are circularly arranged for engagement by a resilient slide contact 86. The carrier or hub II of contact 66 is mounted on the shaft Bl of the idler gear 51. It is desirable to make the ratio of gears 58 and 51 (Fig. 3) the same as that of gears 50 and 30 (Fig. 2) so that the angular speed of the slider 86 (Fig. 1) is the same as that of the stylus 25. If the apparatus is intended for use as a multiple recorder, the rotary speed of the slider must be an integral multiple of that of the stylus.

. 6 v stance, by driving the slider from shaft 49 (Fig.

3), provided the ratio of gears 58 and 51 is an integral number or fraction.

The electric control and measuring circuit for operating the recording apparatus-includes as a rule, besides the above-mentioned impedance or potentiometric device, some measuring gauge or other circuit means responsive to the quantity whose variations are to be recorded and has also a relay associated with the gauge or circuit means as well as with the impedance or potentiometric device. One of the many control circuits applicable with the above-described recording apparatus is shown diagrammatically in Fig. 4. Only those mechanical parts of the recorder are represented in this schematic showing that have to be referred to for explaining the operation, and these parts are denoted by the same reference characters as are used in Figs. 1 to 3 for corresponding items. The feed screws and other transmission and drive means for moving the stylus assembly 5 axially along the drum D are not shown in Fig. lbecause it will be clear from the foregoing that this longitudinal motion is nular member M, while rotated by gear v derived from the idler gear bl and that the anthrough shaft l9 and the bevel gears 52, 53 driven by. motor b5, advances simultaneously from the left to the right of drum D as shown in Fig. 4. During each rotation of the stylus, the slider 66 of potentiometer P passes once through its complete cycle relative to the appertaining resistor 6% here shown simply as a slide wire.

The drive and transmission mechanisms are at ground potential. The insulated drum D is connected to a control circuit C l) through the dowel pin lb and a terminal lug Elli (Fig. l). The stylus assembly S is likewise connected to circuit C so that the recording sheet on drum D lies in a discharge gap between the drum suriace and the stylus point. The circuit C includes a capacitor ill, a direct current source or battery.

ll series-connected with a resistor ill, and a relay R whose movable contact is normally biased by a Spllllg it toward a stationary contact lb and switches over to another stationary contact 16 when the relay coil ii is energized to an extent sumcient for overcoming the spring bias. The capacitor is normally connected to the current source ll and hence in charged condi tlon. Mien contact ill switches over to contact is, the capacitor "is is disconnected. from source ii and discharges itself through the stylus and drum, this discharge being of very short dura tion so that a clot marl: is produced on the re cording sheet.

The relay coil ll derives its cnercization from a measuring circuit under control by the potentiometer P. A measuring gauge G. here represented by a thermocouple" although any other type of gauge, impulse or signal transmitter may. be used, is connected across the potentiometer resistor 68, for instance, through an amplifier A.-

quired by coll Tl for actuating the relay contact 13. that the threshold voltage of the relaylies within the range of the expected potentiometric voltage variations. When the slider 8! begins its travel at terminal point It, the voltage drop across relay coil 11 is zero so that the stylus, now

also at the starting point of arota-tion, is de-- 2,401,360 7 8 energized. As the slider 56 travels along resistor ['58 in Fig. 6 correspond to the respective ele- 88 toward terminal point 19, it will reach a point ments 0, 35, 35, 52, 53, 58 and B in Figs. 1 to 3.

where the voltage imposed on the relay coil When. in operation, the motor shalt I54 (Fig. 6) passes through the threshold value. At this mo drives a. bevel gear l53 meshing with a bevel gear ment, the movable relay contact 13 is switched 5 I52 which drives an idler gear I51 and, through over so that a self-terminating short-lasting disgears [58 and ass, causes the feed screws 35 and charge is released and a recording point produced I36, respectively, to advance the axially movable by the stylus. While the slider '56 continues its assembly, including memhers Mil, M and the travel, contact 13 remains in engagement with stylus assembly Blillilg the drum. El, while the contact 16 so that no further recording action member M. stylus are rotated. The electric occurs. At the end point of the slider travel, control of the :reeorclin c aeration r carried the coil circuit of the relay is interrupted. While out by circuit means 1e type ad, by the slider 56 passes from point l9 to point is, Fi at.

contact l3 returns to contact lit thus charging capacitor Til the 1. The note lorig which threshold v chi. 1'1

5'5)? till; "U the su h position lixed rclal resistor M. produced in" also lndi the recorr cording ow. sented by be readily crating the rotation. l

the location of the 1 cording: l diagram is to appear. The rot with oi the drum also of advi'uita. initial lltll. device or will) (not the recorder is mounted so the only one side or" shown) may intro cre'vcnt the drum the drum is conveniently vie to an observer. iromrototing unless That is, by turning knob any part of the diet Due to the fact that the .311

gram can be moved into a desired angular posi tion. of the potentiomei 1"; including the resistor tlon, although when this is done during a recordcorresponding to item in Fig. 4. is rotatable lng operation, the continuity of record d diam together with the drum, the drum rotation does gram will be interrupted a long as the drum is not interfere with the recording operation. Conout of its normal or starting position. Unless this sequently, the drum can he placed into any conis undesirable the recorder need not be stopped. venient position during a recording procedure A modification which avoids such diagram (115- without req ring an interrup 0f the Op continulty will be described presently with refer t n. ence to the horizontal drum typo recorder shown The foregoing description refers especially to in Flgsfiand 7. recorders in. which one coordinate is time and The apparatus according to Figs. 6 and 7 has a therefore the axial translation of the stylus 115 ba structure 3 a recording drum 1), a stylus sembly derived from the drive or transmission assembly S carried by an annular member M, mechanism for rotating the styius- For a and a resistance potentiometer P corresponding 30 corder in which the axial movement represents a to the similarly denoted parts of the recorder premagmwds not pmpertmml to time .3) or 151 (Fig. 6) is not viously described. The stylus assembly is rotated corder)' thg gear 57 about the drum and advanwd mung the drum by connected to the motor drive of shaft 43 (Fig. 2).

but is e d to a separate drive which is conmeans of transmission and drive mechanisms 35 trolled in dependence upon The component map mil igl gffgfi ggiz g fi s gfgi ifgggg fgs nitride represented by the axial coordinate of the e u .1 u,

recording. That is, the rotary drive of the stylus and for pelmimng a briefer dfimripmon of the and the relative axial translating motion between parts thus concerned without loss in clarity, the

stylus and drum can be derived from any two same reference numemis 115mm W suitable sources of motion under control by difdividual items functionally structurally similar femm and nut necessarily mtemwendem quato those of Figs. 1 to 3, except that in Fig. 5 the titles. For many nurposes it is desirable to have Prefix 1 has helm Milled M11058 number's 0f the stylus not rotate continuously and to keen parable items. For instance, cover member NU. m recorder t; t; m a perigd, of tim after each fe d S re I3 5. and ars lfii. I5 W3 a d rotation of the stylus. This can be obtained in tently 9 y I either above-described embodiment by employing a start-stop drive instead or the continuously running and directly coupled motor 55 (see P18. 1).

Another embodiment 01' a recorder which lends itself readily to either time proportional or X-Y recording, is represented in Fig. 8, mainly by an illustration of those of its parts that are difierent from the recorders described previously.

The last two digits of the reference numerals used in Fig. 8 are identical with the numerals of Figs. 1 to 3 wherever similar elements are concerned.

According to Fig. 3, the flange member 229 and gear 230 of the annular member, carrying the 7 rier structure donned of two piston-shaped dist:

members to and 89 which are rigidly interconnected by two rods to and ill. The rods are slidebly guided in two tubes 92 and 93 firmly mounted on the base plate 2E8. A centrally located reed screw M is iournalled in plate lit and engages a nut 95 rigidily attached to a neck portion 9% of olislrmernher 89. A gear 9? on feed screw 9d serves to revolve it and i geared either to the drive or transmission means (not shown in ll proportional operation is intended or to a sen crate drive under: not necessarily time pro gzortiohal control when X-Y recording is intend drum cylinder is irictionally held on L9e portions of disk member and 89 it cannot rotate relative thereto unless lznoio Std is turned manually. Knob serve also to pull the drum out oi its seat for loading t with recording paper. Referring to rooortional operation, the drum is ioovvu in 8 when starting the on the stylus i rotated and intermit ergised the manner explained alcove, the icon screw 96 lifts the nut to and the en carrier structure and thereby causes the to protrude more and more from the plate Elli, choosing the diagram as it is being written he rotating stylus. it will be under stood that the drum carrier can be connected with the normally stationary portion of e. poten= tlometer explained withrelerence to d it is desired to permit rotating the drum ey hand without interruption oi the diagram orre= cording operation. An apparatus of this tyne is also applicable cases where the rotation of the stylus is not continuous but occurs intermittently in, regular or irregular intervals as obtainable by means of start-stop drives, for instance.

While the above-described embodiments in volve the use oi electro-responsive recording all for rotating the stylus when time= The apparatus shown in Fig. 9 is in many respects similar to that of Figs. 1 to 3 or 6. Asa

matter oi fact, the recorder may be identical with that 01 Figs. 1 to 3 as regards all parts denoted in Fig. 9 by the same reference characters as those used in Figs. 1 to 3. The stylus 325, however, is an ink pen or the like device which writes a line 380 on the recording surface of drum D in accordance with any relative motion between the drum and the member M carrying the stylus. Obviously, a, recorder of this kind does not operate with a control circuit as typified by Fig. 4; but instead requires the rotary stylus motion. to be controlled in dependence upon a control magnitude. Assuming, for instance, that the relative axial translation between stylus and drum is time proportional, the rotary motion of the stylus is to he controlled in accordance with the variations of the quantity to be recorded versus time. To this end, the-motor 355, used for rototing the stylus carrier M through gears 53 and lit, shalt iii and gear BI) and til, is of the reversible type. Its two reversing circuits are connected to a current source t'l through a movable contact tilt and the stationary contacts 315 and tilt of a polarized relay whose control coil illl is connected to a measuring circuit which includes the potentiometer P. The slider 6% of the potentiometer resistor 368 is connected by shalt and gears Ell, ed with the transmission shaft of the stylus drive so that it rotates together with the stylus with a transmission ratio or izl. Hence, eoch rotary movement of the stylus causes 0. simultaneous adjustment oi-the slider contact along resistor 5W8.

The terminal points tilt and are of resistor 358 i are connected with lined and variable impedance devices end ill}, respectively. The impedance device to represents n measuring gauge which choirs-es impedance value in response to the phenomenon or cuontity to he recorded. Resistor impedance devices 9d and 8t dorm a loridge circuit whose sero lam-rich or output diagonal includes the relay coil t ll, while input or teed diagonal is connected to a current source lilo oi constant volteco.

iii)

till

.6 or film motor or, in the case 0! an X-Y recorder,

its long es the two impedance values oil devices 96 so ore equal or o elven ratio, the hridce circuit is balanced when the'slider engages a Toelciice point, for instance. the endpoint,

or resistor 868. in this slider. position, no voltage drop occurs not so the relay coil 37? so that contact ll 23 resumes inonerativo mid-position. As e. result moi-or 8% is dccnerulsed and at rest, and the stylus oerlormc no rotation. impedance oi gouge til) dcnartsilrom. the ice-lance value, c. volts-go drop appears across relay coil till in a direction depending upon that oi the imped once departure and causes contact tilt to engage contact fill") or lid. The the ellect oi chor sizing the motor .li'ld so that stylus etc end slider are rotated in the direction in which the slider reduces the unbalance oil the bridge circuit until scie ce is reestablished and the motor stopped.

sit, the stylus and slider perform a iollow up motion whenever an impedance change in 08 occurs and tend to maintain an angular which, at any time. is indicative or the to be measured. Therefore. the solidve tilt recorded by the apparatus repremeasured quantity versus time. The Weneloting means are not shown in Fig. 9, but may be identical with those shown. in Fig. 1, Axial displacement may be achieved by a cents When the by any reversible motor responsive to the quantity to be recorded along the abscissa.

Recording apparatus according to the invention are, of course, also applicable for recording nonelectric variations and, for such uses, need not necessarily be provided with the above-described driven potentiometers. Referring, for instance, to Fig. 9, the rotary stylus assembly, instead of being driven by a motor, can be linked directly to a measuring element producing a rotary motion. For example, in a strain-stress recorder, the stylus carrier can be driven by a mechanical gauge whose angle of rotation is proportional to a deformation or other stress, to be measured, while the axial translating device may be coupled with the strain-measuring device or transmission of the testing machine. Such a recorder need not be provided with electric control means.

While the above-described embodiments of the invention contain an electric potentiometric device for controlling the recording operation, it will be understood that the above-elucidated principles and structural features of the invention are also applicable to recording apparatus having other types of control devices associated therewith. This will be more fully understood from the following example of a recorder having a me... chanical potentiometric or tensiometric relay control device.

Referring to Fig. 10, a drum and stylus mechaanism with rotatory and translating drive means designed in accordance with the above-described embodiments is combined with a special type measuring relay SR whose movable contact is biased by an oscillating spring mechanism which changes the biasing force or torque of the spring through a given, range of variation in much the same way as. the effective potentiometric voltage is changed and applied to a relay in elccl tentiometric control devices of the type described. Since the operating principle of oscillatory spring relays is lthowu such, th following description is lib-Jilted to its essentials and its adaptation to, and combination with, rotating stylus recorder in accordance with the invention.

As in the embodiments of Figs, l through the apparatus represented by big. it) has a drum D provided with a knob 20 and surrounded by an annular carrier M for the stylus til. Member M is rotated by means of gear Efl, shaft M, bevel gears 51 and 53 by a motor 55, while pci'iol'niing an axial translating motion relative to drum l) which is produced by means (not shown in Fig. similar to those of Figs. 1 through 6, for instance. Gear 456 and 451 form a transmission between the stylus means and the relay SR and drive a cam O in synchronism with the stylus rotation.

The relay SR is of the moving coil galvanometer type. It has a permanent field magnet E and a moving coil 411. The coil is mounted on a shaft F which carries a contact cooperating with stationary contacts 415 and 418 for controlling a discharge circuit C of the type described above in conjunction with Fig. 4. The coil 4'" is electrically connected to a measuring or control gauge G, through an amplifier A, if desired. The biasing torque, to be overcome by that of the energized coil 411, is provided by a spiral spring 414. The inner end of spring 414 engages shaft F and the outer end is attached to a stud G mounted on a gear H which is freely rotatable about shaft F. Magnet E and contacts 415 and 418 are mounted on the stationary structure of the recording apparatus and thus remain stationary during the operation of the relay. Ht :ice,

the biasing torque imposed on coil 411 by spring 414 depends on the angular position of stud (3 relative to the stationary parts and can be varied continuously by rotating the gear H. Such rotation is effected by means of a gear I whose shaft carries a follower arm K with a stop L held against cam 0 by a spring N.

When the stylus drive rotates in the direction of the arrow Q, cam O completes a full rotation for each rotation of the stylus and moves the follower K from a lowermost to an uppermost position. Upon completion of each rotary cycle, the follower drops back to the lowermost position. As a result, the spring 414 has lowest tension at the start and increases it gradually to a maximum at the end of each cycle. At the time point with in each cycle when the coil toruue caused by the measuring quantity effective in gauge G.- exceeds the biasing torque of the spring did, the movable contact of relay SR switches from contact 415 to contact 41b and causes the stylus to write a recording mark. This takes place at an earlier or later moment within each cycle depending upon the magnitude of the measuring quantity. The angular position of stud 6:, gear 1, arm K or stylus to at the occurrence of the switcl'iing over is indicative of this magnitude. Consequently, the position of the recording mart: produced by stylus. relative to the recording surface or sheet, is also representative of the magnitude to be measured.

The embodiments of lBCUl'Cllllg apparatus shown ii and 12 are related to that of l3 and l in that they permit the attendant oi observer to rotate the i'coo Ciel" drum in order to place the recorded Ztl'll into a convenient on without interrup oi the recording ration. While in the embodiment of Figs. 6

on t rol device, it is wit invention to accomplish 'tlparatus in which one of the relatively movable ts of the control device is stationarily mounted. this end, I provide the recorder with a gear transmission whose two input shafts or gears are connected with the recorder drum and stylus respectively and whose output shaft or gear drives the control device at a given ratio to the differential relative motion between drum and stylus with respect to the peripheral direction of the drum. Both embodiments of Figs. 11 and 12 are designed in this manner.

While the showing in Figs. 11 and i2 is schematic, it will be understood that the base structure B, the drum with knob 20, the rotary member M carrying the stylus 25, shaft 43, gears 50, 52, 53, and motor 55 are similar to the correspondingly designated parts of the recorder shown in Figs. 1 through 5. As a matter of fact, this portion of the apparatus, as well as the axial translating means of the stylus assembly (not shown in Figs. 11 and 12) are preferably of substantially the same design as the corresponding it in accordance with another control magnitude.

4. A recording apparatus comprising a base structure, a recorder drum mounted on said structure, a carrier member coaxially rotatable relative to said drum, stylus means mounted on said member so as to be rotatable together therewith for producing a record along the peripheral surface of said drum, means for rotatably supporting said member, a threaded shaft extending along said drum for engaging said supporting means in order to move it axially with respect to said drum, another shaft extending along said drum and having gear means for engaging said member in order to impart rotation thereto, drive means geared to said two shafts for revolving them in a given relation to each other, and control means for rendering said stylus means operative to produce said record at points oi. its travel relative to said drum in accordance with a control magnitude to be recorded.

5. A recording apparatus comprising a base structure, a recorder drum mounted on said structure, a carrier member coaxially rotatable relative to said drum, stylus means mounted on said member so as to be rotatable together therewith for producing a record along the peripheral surface of said drum, means for rotatably supporting said member, a threaded shaft extending along said drum for engaging said supporting means in order to move it axially with respect to said drum, another shaft extending along said drum and having gear means for engaging said member in order to impart rotation thereto, base structure for control means disgrzltude and comprising an impedance dev ountcd said base structure and geared one oi said shafts so to vary its impedance in a given relation to the revolution of said oh ft.

6. A recording a lotus comprising a drum for accommodating a recording sheet, stylus means arranged. for 1121 511 i the sheet and being; rotatable about the axis cl said drum, said drum and stylus means being axially displaceable relatively to each other, drive means for imparting rotation to said stylus means, a relay mechanism having electric contact means for controlling the marking operation of said stylus means in accordance with a quantity to be recorded and being provided with contact biasing means having a movable member for varying the biasing eflect of said biasing means through a given range of variation, said member being connected with said drive means so as to move in a given relation to the rotation of said stylus means, and drive means for axially displacing said stylus means and sheet relative to each other.

7. A recording apparatus comprising a rotatable drum for accommodating a recording sheet, stylus means disposed for marking said sheet and being rotatable about said drum, said drum and stylus means being axially dlsplaceable relative to each other so that said stylus means is operable when said drum is non-rotating, ,a device disposed for controlling the marking operation of said stylus means and having a stationary part and a member rotatable relative to said part for adjusting the control effect of said device, and a planetary gear transmission having two input gears connected with said drum and stylus means, respectively, and an output gear connected with said member for rotating it in a given ratio to 16 resultant relative rotation between said drum and said stylus means.

8. A recording apparatus comprising a rotatable drum for accommodating a recording sheet, stylus means disposed for producing a record on said sheet and being rotatable about said drum,

said drum and stylus means being axially displaceable relative to each other so that said stylus means is operable when said drum is nonrotating, a potentiometric measuring device disposed for controlling the writing operation oi said stylus means in accordance with a quantity to be recorded and having a stationary member and a rotary member cooperative for varying the potentiometric control effect of said device,

- and a diil'erential transmission connecting said fill ill

till

drum and said stylus means with said rotary member so as to rotate the latter in a given ratio to resultant relative rotation between said drum and said stylus means.

9. A recording apparatus comprising a rotat able drum for accommcdatin ecording sheet, stylus means disposed for or g a record on said sheet and being rotatabl rout said drum, said drum and stylus means c g axially displaceable relative to each other not said stylus means is operable when ion-"rotatring, a relay meclicu c contacts l'cr controlling the stylus means in accoi'oi recorded and being prov ling means having a s tary member coopeing effect of said transmission ccnncc stylus means rotate the i stylus means.

10. A recording apparatus c maily non -rotating but 1, for accommodating a rec means disposed prodi sheet and being rotatable u on drum and stylus means i in able relative to each otll means is operable when said ing, an oscillating spring rein" liming electric contact means for controlling tlic writing operatlon of said stylus means in ac lance with a quantity to be recorded being provided with a contact biasing spring and a movable member ior varying the biasing effect of spring through a given range of variation, and a differential gear transmission connecting said drum and said stylus means with said member so as to move said member in a given ratio to resultant relative rotation between said drum and said stylus.

11. A recording apparatus comprising a drum for accommodating a recording sheet, a revolvable annular member surrounding said drum and having an annular gear coaxial to said drum, stylus means mounted on said member for producing a record on said sheet, drive means having a gear in engagement with said annular gear for revolving said annular member, and drive means for producing relative motion between said drum and said member in the axial direction of said drum.

12. A recording apparatus comprising a drum for accommodating a recordin sheet, an annular member surrounding said drum, stylus means mounted in said member for producing a record 17 means in engagement with said member for permitting it to revolve relative to said support about said drum, drive means comprising a feed screw extending in parallel to the axis of said drum and member for imparting thereto relative motion in the axial direction of said drum, and drive means engaging said member for imparting revolving motion thereto.

13. A recording apparatus'comprising a stationary structure, a normally non-rotating but manually rotatable drum.for accommodating a record sheet, said drum being secured to said structure so as to be removable therefrom, an annular member surrounding said drum, a nonrotary support secured to said structure and hav-v stylus mean being axially displaceable relative ing bearing means in engagement with said memher for permitting it to revolve relative to said support about said drum, a stylus mounted on said member for producing a record on the sheet, drive means comprising a feed screw extending parallel to the axis of said drum and member for imparting thereto relative motion in the axial direction of said drum, and drive means engaging said member for imparting revolving motion thereto.

14. A recording apparatus comprising adrum for accommodating a record sheet, an annular member surrounding said drum, a stylus mounted on said member for producing a record on the sheet and being movable relative to said member toward and away from said drum, a non-rotary support having means for engaging said member so as to permit it to revolve coaxially about said drum and being axially displaceable along said drum, drive means having a feed screw extending in parallel to the axis of said drum, coupling means disposed on said support for engaging said feed screw so that said support is displaced by said drive means when said screw and coupling means are operative, control means on said support for disengaging said coupling means from said screw to permit displacing said support independently of said drive means, and means on said support for holding said stylus away from said drulm when said coupling means is disengaged.

15. A recording apparatus comprising a normally non-rotating but manually rotatable drum for accommodating a recording sheet, stylus means disposed for producing a record on said sheet and being rotatable and axially displaceable relative to said drum so as to be operable when said drum is non-rotating, drive means for imparting rotation to said stylus means, drive means for axially displacing said stylus means relative to said drum, electric means for trans= Initting control impulses on said stylus means so as to cause it to produce recording marks on said sheet indicative of a phenomenon to be recorded, an oscillating spring relay forming part of said electric means and having a base structure, contact means'on said structure for controlling said impulses and being provided with a contact biasing spring, and a member movable relative to said structure for varying the biasing effect of said spring through a given range of variation, and gear means connecting said relay with said drum and said stylus means-for producing relative motion between said structure and member in a given ratio to resultant relative rotation between said drum and said stylus.

16. A recording apparatus comprising a rotatbeing rotatable about said drum, said drum and to each other so that said stylus means is operable when said drum is non-rotating, a device disposed for controlling the marking operation of said stylus means and having a stationary part and a member movable relative to said part for causing said stylus means to mark the sheet in. a position relative to said drum depending upon a singular position of said member relative to said part, and a differential transmission having two input elements connected with said drum and said stylus means respectively, and having an output element connected with said member for moving said member in a given relation to resultant relative rotation between said drum and said stylus means.

1'7. A recording apparatus comprising a cylindric electrode for accommodating a record sheet, an annular member coaxial with and rotatable about said drum, a stylus electrode mounted on said member for marking the sheet when electrically energized, means for displacing said member in' the axial direction relative to the sheet, said annular member having a concentric annular gear, a shaft extending along and in parallel to said cylindrlc electrode and having a gear meshing with said first gear for rotating saidlmember, a drive connected with said shaft and said displacing means for operating said shaft and said displacing means simultaneously in a given ratio to each other, an electric contact device connected with said drum and said stylus electrode for controlling the marking operation of said stylus-electrode, and condition-responsive control means disposed for controlling said contact device and including a member rotatable over a given'range in order to cause said contact device to energize said stylus electrode when said latter member passes through a position indica: tive of a condition to be recorded, and gear means connecting said latter member with said shaft so that said latter member is driven simultaneously with and in a given relation to the rotation of said shaft.

18. A recording apparatus comprising a cylindric electrode for accommodating a record sheet, an annular member coaxial with and rotatable about said drum, a stylus electrode mounted on said member for marking the sheet when electrically energized, a non-rotary structure having bearing means in engagement with said annular member, said annular member having a'concentrio annular gear, a shaft extending along and in parallel to said cylindric electrode and having a gear meshing with said first gear for rotating said member, a ,feed screw extending in parallel to said cylindric electrode and engaging said structure for displacing it along said cylindric electrode, gear means coupling said shaft with said feed screw, a drive motor far causing said gear means to revolve said shaft and said screw in a given ratio to each other, an electric contact device connected with said drum and said stylus electrode for controlling the marking operation of said stylus electrode. and COllCillllOi'i l fESDOIlSlVB control means disposed for controlling said con tact device and including a member rotatable over a given range in order to cause said contact device to energize said stylus electrode when said latter member passes through a position indicative of a condition to be recorded, said latter member being, geared to said gear means so as to rotate in a given ratio to the revolution of said shaft and said feed screw.

REINHARD K. HELLMANN. 

